The physiology and pathology of membrane (contact or surface) digestion of the three main components of the food of animals and man is a rapidly developing field, and there is little doubt that newer ob- servations will become available as time progresses. As the dis- coverer of the phenomenon of membrane digestion, Professor Ugolev is well aware of the relative infancy of this subject, and in presenting the book at this time his primary purpose was to acquaint the reader with the experimental basis for the observed phenomenon and to stimulate interest in the further work required for the...